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8 Easy Steps to Bypass Oil Injection on a Jet Ski [Video]
You can bypass the oil injection system on a jet ski in eight easy steps:
- Read the service manual
- Drain the oil tank, fuel tank, and fuel lines
- Remove the carbs and plug the inlets
- Remove the oil pump and install a block-off kit (depending on the model)
- Remove the oil reservoir and the oil lines (depending on the model)
- Fill up with premix and spray oil into the carbs
- Rejet the carbs if needed
- Remove the “low oil” alarm
We at JetDrift have compiled all you need to know into this step-by-step guide!
How to Bypass Oil Injection on a Jet Ski
1. Read the Service Manual
If you want to bypass the oil injection system on your jet ski, it’s highly recommended to read its service manual.
It’s essential for you to study and understand how oil injection works on your jet ski, as the design of the systems vary depending on the model.
This is because on many 2-stroke jet skis, the oil injection system is intended to lubricate the crankcase or other parts in addition to the carbs.
For example, you have to leave the oil tank in Sea-Doos since their rotary valve gear is lubricated by the 2-cycle oil. Other models require you to leave the oil pump in place, even if you convert your jet ski to premix.
It’s also good to know that most fuel-injected 2-stroke jet skis can’t run without an oil-injection system.
The general rule is that injectors on 2-stroke fuel-injected Yamaha WaveRunners are typically planted in the air intake, so that these machines can be switched to premix.
When it comes to other brands, on Polaris Ficht Direct Injection engines, Sea-Doo RFI and DI engines, and Kawasaki DI engines, the oil-injection system can’t be removed.
This is because the injectors are mounted on top of the cylinders on these engines, so removing the oil pump on these skis would leave their bottom end without any lubrication.
As you can see, jet skis’ oil-injection systems vary from one model to the next!
Therefore, if you’re not comfortable doing this mod, leave it to a professional. Keep in mind that doing it wrong can lead to major engine damage!
Also, be aware of the cons of the oil pump delete, as running on premix often results in excessive smoke and fouled spark plugs.
2. Drain Oil and the Fuel Tank
Before removing the oil pump from your jet ski, you have to drain the oil reservoir. You also have to drain the fuel tank and fuel lines since they are filled with regular gas instead of premix.
Use a simple suction pump to drain the oil reservoir. Then disconnect the lower hose from the oil reservoir, attach the pump to the fitting and remove the remaining oil.
If you can’t suck the reservoir dry, place the oil line into the hull and let the rest of the oil drain into the bilge.
3. Remove the Carbs
You also have to remove the carbs and cap the oil inlets to prevent vacuum leak issues.
Once the carbs are pulled out, you may want to consider rebuilding them if it appears necessary.
4. Remove the Oil Pump and Install the Block-off Kit
Locate the oil pump and remove it, but only if it just feeds the carbs! If the pump is intended to feed other parts of the engine, you have to leave it in place and only block the carb outlets.
As a rule of thumb, on Sea-Doos, the oil pump is attached to the magneto flywheel cover under the carbs.
On WaveRunners and Kawasakis, the oil pump is usually located on the front of the engine. If you are unsure where the oil pump is in your ski, follow the oil line from the reservoir to find the pump.
Remove the pump and the cable if featured. Variable-rate pumps feature a cable that is connected to the throttle lever. Older jet skis with a static oil pump lack this cable, of course.
Again, before removing the oil pump, make sure that it only feeds the carburetors (intake manifolds.)
On certain Sea-Doo and Polaris engines, the pump is driven by a shaft that has to be pulled out with pliers.
Removing the oil pump from these engines leaves a tiny hole on the side of the flywheel cover. To seal this opening, you will have to install a block-off plate and a gasket. This kit is available from various aftermarket manufacturers for a couple of bucks.
5. Remove the Oil Reservoir and The Oil Lines
If your jet ski’s oil-injection system is intended to only deliver oil into the carbs, you can consider removing the oil reservoir with the pump and all the oil lines.
But if the system feeds the crankcase or other engine parts, it’s highly recommended to leave the oil reservoir in the ski. You also have to leave at least a sufficient amount of oil in it.
For example, on Sea-Doos, the rotary shaft bearing and gear are fed directly from the oil tank. On these models, the oil reservoir and the appropriate oil lines have to be left in place.
This is why it’s essential to study and understands how the oil-injection system works on your ski.
Removing the wrong oil lines leaves important engine parts without any lubrication, which results in major engine damage!
Also, if you remove any oil lines from the reservoir, make sure to block off the nipple outlet on it. How can you do this?
You can simply cut the line and insert screws in the end. Don’t forget to secure them with a cable tie! You can block off the inlets on the carbs in the same way.
In some cases, the block-off plate comes with block-off caps, which can also be used for this purpose.
It’s also not wise to use the oil reservoir as an auxiliary fuel tank for safety reasons. If you need extra fuel capacity, it’s recommended that you remove the reservoir (if possible) and the fuel tank and replace them with one bigger fuel tank.
6. Fill Up the Tank with Premix
Since your ski needs premix now, you have to drain the fuel tank and the fuel lines. Then make a premix and pour it into the tank.
The exact premix ratio depends on the features of your ski, the brand of oil, and your riding style.
Keeping safety in mind, spray some oil into the carbs before you first start it to lubricate the cylinders.
If you leave the oil reservoir in the hull to lubricate other engine parts, make sure it’s about 1/4 filled.
7. Rejet the Carbs if Needed
Depending on the features on your ski, you may need to rejet your carbs.
But the good news is that the carbs work just as well with premix as they did with oil injection in most cases!
8. Remove Low Oil Alarm
If you bypass the oil-injection system on your jet ski, you probably have to face constant “low oil” fault codes and limp mode.
To eliminate them, you may want to leave the oil reservoir in the ski with some oil. If you want to remove the oil tank, be prepared to tinker with the cables to bypass this low oil alarm.
The exact process may vary from one model to the next, but you can make a good start with this video tutorial:
Conclusion
Bypassing a jet ski oil-injection system is not rocket science, but it requires some skills and special tools.This general guide covers most models, but keep in mind that oil-injection systems vary depending on the make and model.
Therefore, it’s highly recommended that you do your research for model-specific instructions. Best practice is to study your ski’s service manual as the first step to understand how this system works on your ski.
Don’t forget that doing this modification wrong can lead to various types of engine damage. If you are not comfortable doing this, best practice is to leave it to a professional!
Disclaimer: This post is for general information purposes only. Before you do any maintenance/modification on your jet ski, always read its service manual and follow the manufacturer’s recommendations!
